In theory, fly-fishing is a simple sport: Pick a body of water, choose a fly-fishing rod, select your “fly” (or bait), tie a secure knot, cast your line and, hopefully, land a fish on the other end.

September is often a great time for fly fishing because the days get shorter and cooler, and the trout are starting to show some activity, according to Drifthook. October, when brown trout season ...